Biomedical subjects

K Ruoss

Publications and source records attributed to K Ruoss.

4 recordsLinked to original sources

PubMed2003

Isotropic apparent diffusion coefficient mapping of postnatal cerebral development.

Diffusion-weighted imaging (DWI) allows us to image the motion of tissue water. This has been used to demonstrate acute ischaemia. Diffusion imaging is also sensitive to water movement along neuronal tracts. Our objective was to map brain maturation in vivo using maps of apparent diffusion coefficient (ADC). We studied 22 children without neurological disease aged between 2 and 720 days. MRI was performed at 1.5 tesla. Multislice single-shot echoplanar DWI was performed at b 0 and 1000 s/mm(2). ADC maps were generated automatically and measurements were performed in the basal ganglia, frontal and temporal white matter and the pons. There was a decrease over time in water diffusion in the areas examined, most marked in the frontal (0.887-1.898 x 10(-3) mm(2)/s) and temporal (1.077-1.748 x 10(-3) mm(2)/s)lobes. There was little change, after an initial decrease, in the basal ganglia (0.690-1.336 x 10(-3) mm(2)/s). There was a difference in water diffusion between the anterior (0.687-1.581 x 10(-3) mm(2)/s) and posterior (0.533-1.393 x 10(-3) mm(2)/s) pons. These changes correlate well with those observed in progressive myelination: the increased water content probably reflects incomplete myelination and the decrease with time in water motion reflects the increase in myelinated brain.

Brain Mapping↗

PubMed2001

Diffusion-weighted MRI of middle cerebral artery stroke in a newborn.

Diffusion-weighted MRI of the brain is becoming clinically available as a tool to investigate cerebral ischaemia. We report a newborn girl presenting with seizures in whom diffusion-weighted MRI showed a large hyperintensity in the area perfused by the left middle cerebral artery. Short-term neurological follow-up before discharge was uneventful and the patient was discharged without sequelae. On follow-up clinical examination, right-sided spastic signs were noted which disappeared with time.

Female↗

PubMed2001

Brain development (sulci and gyri) as assessed by early postnatal MR imaging in preterm and term newborn infants.

OBJECTIVE: To investigate fetal brain development in vivo using early postnatal cranial MRI in term and preterm newborn infants. STUDY DESIGN: 51 infants, 1.5-T whole-body system, extremity coil, spin-echo images obtained in all three planes (T1- and T2-weighted). Independent review by two neuroradiologists (blinded for gestational age and medical history) regarding the development of 12 sulci and 10 gyri using a modified scoring system. Gestational age was obtained either by ultrasound or from the first day of the last menstrual period. EXCLUSION CRITERIA: head circumference <10th or >90th percentile, cerebral malformation, chromosomal/metabolic disorder. RESULTS AND CONCLUSION: Age at study ranged from 23 5/7-43 0/7 postmenstrual weeks. Brain maturation starts in the central area and proceeds towards the parieto-occipital cortex. The frontal cortex develops last. Transition to degrees 1, degrees 2 and, degrees 3 starts at week 25, 32 and 35 in the central cortex and is completed at week 34, 36 and 39, respectively. Our data compare favourably with the two previously published reports about brain maturation. Early MR imaging seems therefore to be suited to study maturation of the fetal brain. This may be of pathophysiological relevance in neonatal intensive care and neurological follow-up studies.

Birth Weight↗

PubMed1989

Flow cytometric detection of mitotic cells using the bromodeoxyuridine/DNA technique in combination with 90 degrees and forward scatter measurements.

Mitotic cells could be well discriminated from the cells in the G1-, S- and G2-phases of the cell cycle using pulse labeling of S-phase cells with bromodeoxy-uridine (BrdUrd) and staining of the cells for incorporated BrdUrd and total DNA content. Unlabeled G2- and M-phase cells could be measured as two separate peaks according to propidium iodide fluorescence. M-phase cells showed lower propidium iodide fluorescence emission compared to G2-phase cells. The fluorescence difference of M- and G2-phase cells was caused by the different thermal denaturation of their DNA. Best separation of M- and G2-phase cells was obtained after 30-50 min heat treatment at 95 degrees C. Mitotic index could be measured if no unlabeled S-phase cells were present in the cell culture. With additional measurements of 90 degree scatter and/or forward scatter signals, mitotic cells could be clearly discriminated from both unlabeled G2- and S-phase cells. The correct discrimination (about 99%) of mitotic cells from interphase cells was verified by visual analysis of the nuclear morphology after selective sorting. Unlabeled and labeled mitotic cells could be observed as pulse-labeled cells progressed through the cell cycle. We conclude that this modified BrdUrd/DNA technique using prolonged thermal denaturation and the simultaneous measurement of scatter signals may offer additional information especially in the presence of BrdUrd-unlabeled S-phase cells.

Animals↗